The AVC-H.264 video data compression-coding standard is well known and represents a new generation of video compression-coding that is expected to supersede the widely used MPEG-2 standard for many applications. AVC-H.264 achieves higher compression ratios than MPEG-2 but at the cost of greater processing complexity. In some aspects AVC-H.264 is similar to MPEG-2; for example, both utilize motion compensation to match current pixel blocks with reference pixel blocks to minimize the differential data that is to be transform-encoded.
One compression encoding option offered under AVC-H.264 calls for use of CABAC (context-based adaptive binary arithmetic coding) of syntax elements produced by transform-encoding (including motion vector information and other side data). CABAC potentially offers substantial additional compression efficiency relative to other types of later-stage encoding, but requires considerable processing complexity, particularly in regard to decoding. CABAC decoders for AVC-H.264 have been written in software for execution on general purpose processors, but the resulting decoder performance has been less than satisfactory in terms of throughput, especially for decoding a high resolution signal. Furthermore, CABAC software or hardware decoding of a bin also may occur before a next bin may be decoded, which may create bottlenecks.